He told Newsarama: "Getting to write a Doctor Who episode, for me anyway, was probably the nearest to being God that I have ever been or will ever get."

Gaiman added that his episode, titled 'The Doctor's Wife', will be "funny and scary and exciting and heartbreaking".

"I kind of hope that it may add to the giant Doctor Who mythos because you always want to leave something nice behind you," he said. "But really [it's] just somebody who's... always wanted to write an episode of Doctor Who... being indulged by the BBC in this folly."

The Sandman scribe quipped that he had felt "a similar feeling of megalomaniac power" while writing his first Batman comic script in 1988.

"I got to bring on Batman and write dialogue for Batman," he said. "But making Batman talk does not actually compare to the feeling of glorious power you get the moment you type, 'INTERIOR. TARDIS.'"

Doctor Who will premiere on April 23 on BBC One in the UK and BBC America in the US.